The invention relates to a clutch transmission having a transmission element, having a clutch element, and having a hydraulic controller which comprises an oil pump and has the purpose of providing pressures and volume flows in the clutch transmission, in which the clutch element is accommodated in a clutch chamber and the transmission element is accommodated in a transmission chamber. Furthermore, the invention relates to a method for lubricating and cooling the clutch transmission.
The prior art has disclosed clutch transmissions in motor vehicles in which the clutch element and the transmission element are activated automatically by means of the hydraulic controller. In addition, the hydraulic controller not only lubricates the transmission element but also cools and lubricates the clutch element by virtue of the fact that the oil pump pumps oil into the clutch chamber. The oil which is necessary for the hydraulic controller is sucked in here from the transmission chamber and directed into the clutch chamber where the oil is mixed thoroughly with air. Then the oil which is mixed with air passes into the transmission chamber again.
In order to prevent air being sucked in even at maximum angles of positive gradient and negative gradient when the motor vehicle is being driven, a high oil level must be selected in the transmission chamber. However, the high oil level results in a low efficiency level of the transmission element, which is due to churning of the gearwheels of the transmission element in the oil. Owing to the churning, the air component in the oil is also increased, as a result of which the compressibility of the oil rises further. However, the rise in compressibility adversely affects the ability to control the components in the clutch transmission, which components are activated by the hydraulic controller. This can lead to adverse effects on the comfort and service life.